This invention relates generally to improvements in water purification systems of the type including a purification element or module for producing a supply of relatively purified water which is stored in a reservoir for convenient dispensing through a faucet valve or the like. More particularly, this invention relates to an improved mechanical float valve assembly for controlling water inflow to the purification element or module in response to the water level within the storage reservoir.
Water purification systems of the type including one or more purification elements or modules in the form of filters and/or reverse osmosis units are generally well known in the art for producing a relatively purified water supply used for drinking, cooking, etc. For example, such purification systems commonly include a reverse osmosis filter or membrane which, in the presence of appropriate flow and pressure conditions, separates an incoming tap or feed water supply into the purified water supply and a relatively impure or reject water supply. In particular, the reverse osmosis membrane functions to remove particulate matter and a wide range of dissolved solids and other contaminants from a portion of the tap water inflow, and to concentrate those contaminants within the reject water supply, often referred to as brine, for waste disposal via a suitable drain. The purified water supply is normally collected for storage within a reservoir, and for ready dispensing on demand through a faucet valve or the like.
One potential disadvantage associated with reverse osmosis purification systems relates to the inherent waste of at least a portion of the tap water inflow, by virtue of the flow of the concentrated brine water to the drain site. This disposal of a portion of the tap water inflow is generally acceptable during normal system operation to produce purified water, during filling of the storage reservoir. However, when the reservoir reaches a filled or substantially filled condition, there is typically at least some continued flow of water through the reverse osmosis membrane to the drain, wherein the amount of water wasted during this condition can be significant and undesirable.
In the past, reverse osmosis purification systems have been designed to include a tap water inflow control valve responsive to filling of the storage reservoir, in order to reduce excessive water waste. More specifically, purification systems have been developed to incorporate a shut-off valve responsive to the pressure within a pressurized storage reservoir to halt tap water inflow to the system when the reservoir is filled. See, for example, U.S. Pat. No. 4,776,952. Other purification systems of the type having an unpressurized storage reservoir have included float-operated solenoid valves responsive to reservoir water level to halt tap water inflow when the reservoir reaches a substantially filled condition. Such electric solenoid devices are, however, relatively costly and include metal components which are conducive to corrosion-caused malfunction resulting in reservoir overflows.
Mechanical float valve arrangements have been proposed for regulating tap water inflow to the purification system. See, for example, copending U.S. Ser. No. 09/141,293, filed Aug. 27, 1998. Such mechanical float valve arrangements utilize a float mounted at the end of a lever arm or the like for shifting a tap water inflow control valve toward a closed position in response to rising water level within a storage reservoir, and to permit re-opening of the control valve in response to a falling water level within the reservoir when water is dispensed therefrom. However, in a reverse osmosis type purification system, the control valve is displaced slowly toward the closed position, resulting in a progressive reduction in the water pressure and flow rate applied to the reverse osmosis purification membrane. In some instances, the water pressure and flow rate will fall sufficiently to preclude further production of purified water for filling the reservoir while continuing to permit a slow flow past the reverse osmosis membrane to the drain. As a result, a further rise in the reservoir water level is prevented so that the inflow control valve is never fully closed and a substantial amount of water can be wasted.
The present invention relates to an improved and relatively cost efficient yet highly reliable mechanical float valve assembly for use in regulating tap water inflow to a purification system in response to the water level within a storage reservoir. The improved float valve assembly of the present invention incorporates an over-center switch means for achieving a substantially snap-action full closure of a tap water inflow control valve in response to rising water level within the reservoir.